When you're packing, remember to limit anything liquid-y to 3.4 ounces (100 milliliters) or less and to place those items in a clear, quart-sized plastic bag, one bag per traveler. Think the usuals, like shampoo, toothpaste, and aerosol or roll-on liquid deodorant (solid deodorant isn't regulated by the 3-1-1 rule).